Polypyrrole functionalized

Furthermore, the utilization of preformed films of polypyrrole functionalized by suitable monomeric ruthenium complexes allows the circumvention of problems due to the moderate stability of these complexes to aerial oxidation when free in solution. A similar CO/HCOO-selectivity with regards to the substitution of the V-pyrrole-bpy ligand by an electron-with-drawing group is retained in those composite materials.98 The related osmium-based redox-active polymer [Os°(bpy)(CO)2] was prepared, and is also an excellent electrocatalyst for the reduction of C02 in aqueous media.99 However, the selectivity toward CO vs. HCOO- production is lower. 

Chandra V, Yu SU, Kim SH,Yoon YS, Kim DY, Kwon AH, Meyyappan M, Kim KS (2012) Highly selective CO2 captirre on N-doped carbon produced by chemical activation of polypyrrole functionalized graphene sheets. Chem Commun 48 735-737... 

Vrkoslav V, Jelmek I, Broncova G, Krdl V, Dian J (2006) Polypyrrole-functionalized porous silicon for gas sensing applications. Mater Sci Eng C 26 1072-1076... 

Eaves, J. G., Munro, H. S., and Parker, D., Anodic elecirodepo.sition of thin films of polypyrrole functionalized with metal bipyridyl redox centers, Inorg. Chem., 26, 644-650 (1987). 

Electrochemical polymerization of 3-alkylsulfonate pyrroles with various lengths of the alkyl chain has given water-soluble self-doped polypyrroles [282]. Moreover, a self-doped polypyrrole functionalized with carboxyl groups was prepared by anodic coupling of 3-carboxymethylpyrrole [283] and was subsequently tested as a proton-pump electrode [284]. 

Functionalized conducting monomers can be deposited on electrode surfaces aiming for covalent attachment or entrapment of sensor components. Electrically conductive polymers (qv), eg, polypyrrole, polyaniline [25233-30-17, and polythiophene/23 2JJ-J4-j5y, can be formed at the anode by electrochemical polymerization. For integration of bioselective compounds or redox polymers into conductive polymers, functionalization of conductive polymer films, whether before or after polymerization, is essential. In Figure 7, a schematic representation of an amperomethc biosensor where the enzyme is covalendy bound to a functionalized conductive polymer, eg, P-amino (polypyrrole) or poly[A/-(4-aminophenyl)-2,2 -dithienyl]pyrrole, is shown. Entrapment of ferrocene-modified GOD within polypyrrole is shown in Figure 7. 

The polymers which have stimulated the greatest interest are the polyacetylenes, poly-p-phenylene, poly(p-phenylene sulphide), polypyrrole and poly-1,6-heptadiyne. The mechanisms by which they function are not fully understood, and the materials available to date are still inferior, in terms of conductivity, to most metal conductors. If, however, the differences in density are taken into account, the polymers become comparable with some of the moderately conductive metals. Unfortunately, most of these polymers also have other disadvantages such as improcessability, poor mechanical strength, instability of the doped materials, sensitivity to oxygen, poor storage stability leading to a loss in conductivity, and poor stability in the presence of electrolytes. Whilst many industrial companies have been active in their development (including Allied, BSASF, IBM and Rohm and Haas,) they have to date remained as developmental products. For a further discussion see Chapter 31. 

Figure 29. (a) Evolution of the absorption spectra of an electro-chromic polypyrrole as a function of the oxidation potential obtained during voltammetry between -900 and 400 mV from a 2.5 M LiCI04 aqueous solution. The voltammetry was performed at a scan rate of 20 mV s 1. (From Ref. 161). (b) Evolution of the absorption spectra of an electrochromic polypyrrole as a function of the reduction potential obtained during voltammetry between 400 and -900 mV from a 2.5 M LiCI04 aqueous solution. The voltammetry was performed at a scan rate of 20 mV s 1. (From Ref. 161). 

Cyclic voltammetric studies involving polymers, 558 and the nature of charge carriers, 561 and the nucleation loop, 557 of poly (3-methylthiophene), 564 and parallel-band electrodes, 570 Cyclic voltammograms as a function of scan rate, 559 involving polymerization, 559 with polyanaline, 566 of polypyrrole film, 581... 

In the area of ion sensing, cation recognition by electrodes containing functionalized redox-active polymers has been an area of considerable interest. Fabre and co-workers have reported the development of a boronate-functionalized polypyrrole as a fluoride anion-responsive electroactive polymer film. The electropolymerizable polypyrrole precursor (11) (Fig. 11) was synthesized by the hydroboration reaction of l-(phenylsulfonyl)-3-vinylpyrrole with diisopinocampheylborane followed by treatment with pinacol and the deprotection of the pyrrole ring.33 The same methodology was utilized for the production of several electropolymerizable aromatic compounds (of pyrrole (12) (Fig. 11), thiophene (13 and 14) (Fig. 11), and aniline) bearing boronic acid and boronate substituents as precursors of fluoride- and/or chloride-responsive conjugated polymer.34... 

The Teixidor team further improved upon this chemistry by covalently linking units of 109 to the polypyrrole monomer prior to electropolymerization.139 A [3,3 -Co(C2B<)H11)2] anion was covalently bound to a pyrrole via a spacer through one of its boron atoms by the reaction of the species [3,3 -Co(8-C4H802-l,2-C2B9H10)(r,2 -(C2B9H11)2] with potassium pyrrole, as functionalization through... 

The critical role of the latter process was clearly shown in the extremely elegant work of Wegner and Riihe (1989) who measured the temperature dependence of the DC conductivity of a range of polythiophene and polypyrrole derivatives as a function of the interchain separation. The derivatives... 

Lately, the accelerating effect of functionalized polypyrrole (PPy) composites consisting of ACF/PPy/AQDS is studied during the biological decolorization processes of azo dyes [50]. This study suggests that ACF/PPy/AQDS play a good catalytic role and accelerate the reductive decolorization of different azo dyes by an anaerobic consortium. But their use in the practical full-scale wastewater treatment still needs to be proved in the future studies. 

Korri YH, Gamier F, Srivastava P, Godillot P, Yassar A (1997) Toward bioelectronics specific DNA recognition based on an oligonucleotide-functionalized polypyrrole. J Am ChemSoc 119 7388-7389... 

Electrically conducting polymer particles such as polypyrrole and polyaniline could also be prepared by dispersion polymerization in aqueous ethanol (31). The oxidation polymerization of pyrrole and aniline has been carried out at the electrode surfaces so far and formed a thin film of conducting polymer. On the other hand, polypyrrole precipitates as particles when an oxidizing reagent is added to a pyrrole dissolved ethanol solution, which contains a water-soluble stabilizer. In this way electrically conducting polymer particles are obtained and, in order to add more function to them, incorporation of functional groups, such as aldehyde to the surface, and silicone treatment were invented (32). 

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